Locking structure for power tool setting



June 28, 1960 H. c. cAssr-:Y 2,942,632

LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheet. l

ATTORNEY June 28, 1960 H. c. cAssEY LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheet. 2

ATTORNEY INVENTOR HAROLD C. CASSEY June 28, 1960 H. c. cAssEY LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheet 5 Smm,

INVENTOR HAROLD C. CASSEY BY {@n/ ATTORNEY June 28, 1960 H. c. cAssEY 2,942,632

LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheet 4 ZZ 8 F|G.7 9

FIG. 8

INVENTOR HAROLD c. cAssEY BY/Qh/ KA,

ATTORNEY June 28, 1960 H. c. cAssEY 2,942,632

LOCKING STRUCTURE FOR POWER TOOL SETTING lNvl-:NToR HAROLD C. CASSEY ATTORNEY H. C. CASSEY 8 Sheets-Sheet. 6

INVENTOR HAROLD C. CASSEY BYM ATTORNEY LOCKING STRUCTURE FOR POWER TOOL. SETTING Filed March 8, 195'? June 28, 1960 June 28, 1960 H. c. cAssEY LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheet 7 FIG. |7-

INVENTOR HAROLD C. CASSEY BY ifa/ ATTORNEY June 28, 1960 H. c. cAssr-:Y

LOCKING STRUCTURE FOR POWER TOOL SETTING Filed March 8, 1957 8 Sheets-Sheena?l 8 ATTORNEY United States l1-"atent LOCKING STRUCTURE FOR POWER TOOL SETTING Y Harold C. Cassey, Landisville, Pa., assigner, by mesne assignments, to American Machine & Foundry Company, a corporation of New Jersey Filed Mar. s, 1957, ser. No. 644,854

9 Claims. (ci. 14s-s) This invention relates to sawing machines, and more particularly to that type of sawing machine known as the radial arm saw in which the sawing mechanismds suspended above the work table `by a cantilever arm.

ln this type of tool the cantilever arm is pivotally mounted on an elevating standard and the sawing mechanisrn is mounted on an anti-friction carriage movable along the arm. The carriage has a vertical pivot for rotating the sawing mechanism in a horizontal plane and further a horizontal pivot for rocking the sawing mechanism for bevel cutting.

Thus the saws have a variety of articulations both sliding and pivotal. It is desirable that these articulations may lbe moved either a measured linear amount or through a measured angular rotation with great accuracy. With respect to `angular rotation it is furtherA desired that more commonly used angular positions have positive 1ocating and locking or indexing means.

lt Iis an object of this invention to provide several of the points of rotation with positive locking or indexing means and frictional locking means for points intermediate the positive locking means.

lt is a further object of the invention to provide an improved form of such locking means and to provide a single action which will operate both the positive locking means and the frictional locking means.

It is a further object of the invention to provide an improved elevating means adaptable to both manual and power operation incorporated in such a tool.

It is a further object of the invention to improve various articulations to facilitate manufacture at reduced cost.

it is a further object of the invention to provide a new and improved adjustable structure to delimit the motion of the carriage along the radial arm.

It is a further object ofthe invention to incorporate certain of the rotary articulations and improved hub adjusting mechanism particularly in `conjunction with improved locking and indexing means.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation may be understood by reference to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a side elevation of the radial arm saw illustreating the improved features of the same;

Fig. 2 is a plan view of the same;

Fig. 3 is a side elevation, partly insection, of the improved radial arm miter index and locking mechanism;

Fig. 4 is a sectional end elevation of the same, taken Fig. 7 is a partial sectional side elevation of the radial f e Patented `lune 28, 1950 ICC -arm Iillustrated in conjunction with the improved saw carriage roller head and yoke indexing lock;

Fig. 8 is a sectional end elevation of the same taken on line 8-8 of Fig. 7, illustrating the yoke indexing lock as well -as a new and improved rip lock; Y

Fig. 9 is also a sectional endY elevation of the radial arm, taken on line 9- 9 of Fig. 7 showing the roller head aligningy and Kadjusting mechanism; v

Fig. l0 is a sectional plan View illustrating an `adjustable bevel bumper canried by the roller head;

Fig. 11 4is an end elevation of the same, taken on line 11-1-1 of Fig. l0;

Fig. l2 is a partial sectional plan View of the radial arm hub, taken on line 12-12 of Fig. 3 illustrating the improved adjustable mounting and clamping mechanism;

Fig. 13 is an isometric view, partly in section, illustrating the improved column elevating mechanism in ccnjunction gwith an elevating brake;

Fig. 14 is =a front elevation of the saw bevel indexing Y and locking mechanism;

Fig. 15 is a side elevation of the saw bevel clamping and locking arm, taken on line 1.5-15 of Fig. 14;

Fig. 16 is fa side elevation of the saw bevel indexing mechanism, taken on line 16-16 of Fig. 14;

Fig. 17 is la rear view `of the saw motor suspension taken on line 17-17 of Fig. l, illustrating the hub adjusting mechanism;

Fig. 18 is a partial plan view, partly in section, of the radial arm, illustrating a modified for-m of the miter indexing and locking mechanism; and

Fig. 19 is fa side elevation, partly in section, of the modified radial arm miter, indexing and locking mechanism illustrated in Fig. 18.

The improved radial arm miter indexing and locking mechanism illustrated in Figs. 1, 2, 3, 4, 5 and 6 is actuated by means of a single lever generally designated as 20 which is conveniently located within easy reach of the operator at the front end of the radial arm 22. The actuating lever 20 consists of a handle portion 24 which forms the connection of a pair of spaced arms 26 and 28 the free ends of both of which are pivotally mounted on a horizontal rod yor shaft 30 held by a pair of suitable lugs 32 projecting from the arm 22. (Figs. l and 2.) Both arms 26 and 28 protrude through suitable openings or slots 34 and 36, respectively, in the top portion of the inverted trough-shaped radial arm 22 so that when the lever 20 `is in its horizontal or locked position, the arms 26 and 2S are substantially tlush with the top surface of the radial arm 22. To the lower portion of arm 26 is pivotally attached one end of an adjustable connecting rod 38 while the other end of said rod is pivotally connected to a wrench lever 40 which engages with the hexagon head 42 of a clamp bolt 44 (Figs. 3 and 4).

4The threaded portion of said clamp bolt engages with a threaded bore in a flange 46 of the partially split hub portion 48, ywhile the smooth portion of the clamp bolt rotatably protrudes through a suitable bore in -a iiange 50 opposite the ange 46 of the partially split portion 48 of the radial arm 22. It is self-evident that any clockwise movement of wrench lever 40 will cause a clamping of the hub 48 of yradial arm 22 to the upper portion 52 of the post or standard 54 while any anti-clockwise movement of said wrench lever 40 would permit free rotary movement lof said radial arm 22 about the upper portion 52 of the standard 54 spacially since said hub is designed in such a manner as to provide a controlled clearance `and tolerance so that less than of movement of the wrench lever 40 may effect a clamping or unclamping of the hub to or from the vupper portion 52 of the standfard 54.

This 'controlled clearance or tolerance is achieved by lever 20 (Figs. l and 2). -able pulley ltl'and provided 'with a predetermined ',amountjotslack (Figs. l andr) which-is takenV up `by a'suitable spring tension device'102, 'theaction of which 'will be'described hereinafter.

splitting the rear portion of said hub 48 as illustrated inV Y. Figs. 2 and4'12 and providing the split portionsY with suitable flanges Se and S8 which in turn are connected by arpair of push-pull clamp screws such as illustrated 1n Fig. l2. Each push-pullvelamp Yscrew `consists of an externally and internally'th'reded sleeve 60 inserted Y a threaded hole 62 .of il'an'ge 58 in such a manner that the lower face 64 of said sleeve engages with the facef6'6 of the ange 56, while a clamp screw 68 is inserted in a suitable hole 7i) `of flange 56'while its threaded portion engages with the internal thread of sleeve 69 in the ange 58."Y An arrangement of this type will permit the hub 48 of radial armv 22 to slightly open andv consequently facilitateVV mounting of said arm Vduring assembly 'operation .after which the push-pull clamp is then Vre-Ksettofolfitain `the desired degree of t of the hub 48 on the upper Yportion 52 ofthe' standard 54. YThe hub 48' of radial arm 22 Vrotatably rests on the top face of an index 'disc 72 which is adjustably secured to the upper portion 52 of Standard 54 by means of a clamp 'screw 74; Thetop face of the Vindex disc 72Y is`r provided with a plurality of accurately milled grooves or slots 76 (Fig. 5) which when'engaged by'an index latch lug 78 (Figi 6) carried by thelradial Y arm 22 will assure the correct setting of said larm during ,cross-cut as well as'miter cut operations. V'v1-he index latch lug 78. srpivotailyr-supported. ina suitable slot 80 of a bossSZfin armiZZ oy-means of a horizontal stud 84 which is integral with and projects fromthe end-of. a

Y Vthread-:dstud 86 of larger. diameterheld hy va suitable Y vthreaded bore-in the. boss `82'.

accuracy in the setting of the radial arm 22. To3latch VAlug 78 is pivotally connected the lower forked end90 of a vertical ,plunger 92 (Figs. `3 and 4) the top'eiid 0f which, by means of a yoke clip 94 isconnected to one l end'ofV acable 96 while the'other end'ofv the'latter is t secured to the Vfree. end of a link or rod 98 Vpivotally` attached to the lower portion Vof arm 28 of the actuating Cable 976 is Vled-'over a suit- Pulley Iii!) Yis loosely supported by an extension 101 (Eig. 4),-integ1al with and projecting from the end ofv the clamp bolt 44. `Plunger ,92 is also provided with a tension spring-104 coniined'in-a 'suitable bore of -boss 82 and acting upon the forked end with the properselected Slot 76 in the indexA disc4 72. To

Yassure the utmost accuracy and to prevent erven,thevslight'-Y Y :est possibility of wiggle ofthe setting of the radial arm 22 theV free forward side` edge106 is'inclose tolerance The. operator simply the latter in thefdirection indicatedV by the arrowshown iny Fig.1l to theA positionv'indicated in dotted-lines fin the fsa'me gure, VThe lifting-,of lever- 20A by the Voperator wiser'novement otwrench lever 49 causing the loosening ofthe clamp bolt `44; and thus/the' unclampingoi-the hub ,Y 48'cf radial arm 22 from the top vportion 5270i the IVstand- Y ard 54.

i Due to the slack provided-'in the cablef96, this iirstfportion of the Ymovement Yof, the lever 20 hasrno effect upon the plunger 92 of the index latch lugs '78,* since `thespring E162 compensates for this .lost motion. However, as soon'asthe cable V96 becomes'taut it impartsfa lifting motion upon the plunger 92AwhichY in turn 'eifectsa disengagement of the latch lug 78 from the slot 76 in the index disc 72 which occurs shortly before the lever 20, pulled by the operator, reaches its frorwardmost position. The machine is so designedv and the slack in cable 96 so calculated that the hub 48'V of radial arm22'is completely unclamped before thelatch lug 78 is disengaged from either one of the slots 76 'in index disc 72. In re-engaging the` latch lug 78 with one ofthe-slots 76 of the indexdisc 72 the sequence,v of course,n reverses itselt` so that a backwardvmovement of lever 20 by the operator eiects rst the engagement of the latch lug 78 with Ythe index disc and then the clamping ofr the hub 481ofriradial arm 272 to the standard. This arrangement constitutes aY tremendous improvement over prior` methods oflocking and indexing done byl two separatev operationsY and in back ofthe machine. e

'As illustrated iIrFg. 5, the index disc 72 is shown with three Yslots 76, corresponding to the l90" cross cut position of arm `22j-angl to thek left `and right=hand 45 9 miter positions.u f It is obvious'thatmorslots could be provided if desired, however, thesear'ethe more common `miter angles, which are accurately located and engaged by latch-lugf78- For 'intermediate angles, the .arm maybe locatedA byY reference to la Adial *orscale (not shown). Thenlever -20'i's-'lnlo'velV to' its lo'ck position to tighten Wrench lever 40 to'holdlthearm 20 in the vdesiredk vangular position.. vIng-this situation plunger 92and latch lug 78 rest on the' top Yotfdisc 72. The, additional slackin cable' 96 is takenrup byrspring 102. Thus, arm 22 may Yb'ealocke'd lin an-nnite riurnberof angular positions by --theffmeans associated with wrench lever 40. It may ibe accurately positioned Yand locked in selected Vpredetermined angular Ypositions-'by the lugV 78 'and the aforementioned lock m'eans Tall operated fromclev'er 20. Y

Y Y The novel indexing .lock Y.for the `saw carriage vroller `head and yoke movement isillustrated :in Figs..7, 8 land 9. :There is. also illustratedon these '.igures a novel t Yarrangement of Hthe fanti-trictionY rollersof Yth'ecarriage. TheV arrangement 'obviates costly ,andl tediousladjustment of the rollers and is substantially!self-aligning.. .In the yroller carriageVV 110 `illustrated,inthe drawings, two pairs of 45.'vangularly1mounted rollers112support the weight of thecarriage while twoipairsfof adjustably .mounted vertically parallel rollers-114 locatedoutwardly of the angular rollers 112. engage with the upper tracks i116 tin arm V22. and act as :guide rollers; The 745 "iangularly .mounted rollers 112 arefmounted andpre-setatthe. time ofimanufacture and :have no fadjus'tmentgmea'n's. .Each pair of the. `vertically. 'parallel' rollers 1'14..isimounted Ton .an

adjustable block 118, each of kwhich in turn is heldin position-in a slotted lug i1201byf2m'eans Vof a lpairoi horizontal set screws 122/andbapair of 'verticalV set 'screws 124. Adjustment and alignment iisjfmade lby f tightening the vertical screws. 124 to alpoint that .just permits v.the

Y Y Y n V carriagellto reciprocate lalongearm122. .iEa'ch vertical Vslidingv contact with the end of a guide screw 108(Fig. 6)

inserted in a suitable threaded hole` in boss 82. Y

Y The change ofthe position ofthe radial arm fromY Y across cut position to a'miter cut position,Y is extremely Y eicint, simple and/convenient, K grasp'sthe handle 24 ofthe actuating Vleverl 2Q and moves set screw-124 isprovidedjwith a l'oclcscrew. 126 to hold said set screws in adjustedposition.. 'This orientation -eliminatesthe necessity of adjustment on:l all :pairs of 'roll- Y ers. Itf makes the adjustment automatic..during the life lof the vrollers and withoutzresort'to use. ot flight .means for=testingrthe-adjustment; i Y t Y A:A sawfarrying .yokelZS rotatablysuspendedlfrom the; carricnmember (-13.0. of .the roller' carriagefl'l .by -meansvof afkingibolt 1132'- (iFfig. 8)'therleft hand :threaded upper portion of 'whichfengages with-a .threaded bore in a hub 134 ofa yokeclantp-'l1a1i"clle-136..Y By: moving. the Y -latter:horizontally lclockwise:orlanthclocliwise :the .yoke may he unclamped and unlockedor clampedandzlocked respectively;flheftopflportionoffthe yoke .A128 is. .provided with fourV conical holes 138 gspaced 90 apart. Each lhole depending :on: the `desired setting :of the 'saw may be engaged by the conical end of a springfmounted plunger 140. The latterf vertically and? slidably mounted A in aA plunger, housing .1.42.A suitably. secured .to the carrier memberllf! 'The plungerflitselflis urged Www i downward by a suitable tension spring 144 surrounding the stepped shank 146 of the plunger and connned Within the plunger housing 142. The upper portion of the plunger shank 146 carries a pin 148 (Fig. 7) which engages with the forked arm 150 of a bell crank lever 152 which straddles said shank and is pivotally supported by means of a stud shaft 154 held by a pair of suitable lugs 156 projecting from the plunger housing 142. The bell crank lever 152 and consequently the plunger 140 is activated by means of a suitably shaped camlike actuator lug 158 which is integral with and projects from the hub 134 of the yoke clamp handle 136. As mentioned heretofore, a horizontally clockwise movement of the yoke clamp handle 136 -will rst loosen the king bolt 132 and thus effect an, unlocking of the yoke 128 from the carrier member 130 and second, upon continued movement cause the activator lug 158 to engage with the bell crank lever 152 and etect a lifting of plunger 140 and thus cause a disengagement of the latter from one of the conical holes 138 in the upper portion of the yoke 128. The latter may now be turned 90 or 180 as desired, upon which an anticlockwise movement of handle 136 rst permits the plunger '140 to engage with that hole 138 which corresponds with the desired position, after which, upon continued anticlockwise -movement of handle 136 the king bolt 132 is tightened to further eiect a frictional locking of the yoke 128 to the carrier member 130. To provide maximum convenience and safety the yoke index lock can only be actuated and the yoke turned when the roller carriage 110 is in its extreme forward position on the radial arm 22. A suitable clearance hole 164 (Figs. 1 and 2) for the upper end of shank 146 provided in the track structure at this point only of the arm 22 permits the plungers :140 to be lifted by the bell crank lever 152 suticiently to enable said plunger to disengage from one of the holes 138 of the yoke 128.

To assure the correct tension of the king bolt 132 at the time of the assembly of the machine as well as equip the machine with adjusting means of said tension due to wear and tear, the upper portion of the king bolt 132 is provided with a hexagon end 160 (Figs. 2 and 8) which carries a suitable wrench 162 by manipulation of which said tension may be adjusted to any desired degree.

In order to lock the roller carriage 110 to the arm 22 after the saw carrying yoke is turned to rip position, i.e., with the saw in a plane extending transversely of arm 22 the machine is provided with a unique rip lock which consists of a U-shaped rip lock shoe 166 (Figs. 7 and 8) the upper free end of which slidingly engages with a rip lock plate 16S which extends substantially over the full length of the arm 22 and is suitably secured to one of the tracks 116 within said arm. The lower end of the lock shoe 166 is provided with a threaded bore 170 (Fig. 8) which engages with the threaded upper end of a vertical stem 172 which is rotatably supported in a suitable bore in the center of the king bolt 132. To the lower end of stem 172 is secured a knurled hand knob 174 by means of which said stem may be turned clock or anti-clockwise. The upper free end of stem 172 carries a lock cap 176 and adjacent the upper-end of the threaded portion of said stem is provided a cotter pin 178. Adjacent the upper end of the smooth shank portion of the stem 172 is also mounted a snap ring 180.

Figs. 7 and 8 illustrate the rip lock mechanism in fully clamped or locked position. In order to unlock the same the operator turns the hand knob 174 counter-clockwise which will cause the snap ring 180 to come to rest on the top end of the king bolt 132. Continuing the counter clockwise rotation of the knob 174 will cause the rip lock shoe 166 to ascend until it is arrested by the cotter pin 178. With the shoe 166 in this raised and unclamped position the roller carriage 110 may be moved freely by the operator by means of a suitable arm 182 (Fig. l) secured to the iront edge of the carrier member 130. 1

In order to provide means for an adjustable -stop of the. roller carriage the carrier member 130 in a suitable bore 184 (Fig. 10) supports a horizontal shaft 186 provided with a plurality of spaced annular grooves 188 each of which, depending on the setting desired, may be engaged with a spring-loaded slotted bracket 190 slidably secured to the rear edge of the carrier member by means of screws 192. (Figs. l0 and Vl1.) TheY rearwardly projecting end of the shaft 186 also carries a bumper head 194 provided for the purpose of engaging with a stationary bumper 196 (Fig. 1) when the roller carriage is moved to its backward stop position by the operator. This backward stop position can easily be Vchanged by simply pressing against the side of the slotted bracket and by moving the shaft 186 either in or out and then permitting bracket 190 to reengage with the selected slot 188.

In order to assure proper angle or bevel cutting the machine is also equipped with a new and novel bevel index and lock control mechanism-such as illustrated in Figs. 14, 15 and 16. For this purpose the front motor trunnion 200 of motor M is provided with an index ange 202 concentric and adjustably secured to said trunnion by means of screws 204. Index ange 202 is provided with a plurality of suitable bevelled notches 206 spaced 45 apart which may be engaged by a correspondingly shaped index lug 208 secured to an index lever 210 which is pivotally mounted on the lower front end ofthe yoke 128 by means of a suitable stud 212 locked by means of a set screw 214. Index ange 202 by means of suitable bosses and screws 216 carries a suitable circular dial or scale plate 218 which, of course, is provided with suitable cutouts (not shown) to permit the index lug 208 to engage with the notches 206 in flange 202. A suitable pointer 220 (Fig. 14) is also provided. The lower front end of the yoke 128 is split and provided with a space 222 to permit clamping and locking of the trunnion 200 after the desired setting is accomplished. The clamping of the trunnion is accomplished by the manipulation of a lock 1ever224 which at its lower end is provided with a threaded bore 226 which engages with the threaded end of a clamp screw 228 passing through the split front end of the yoke 128 as illustrated in Fig. 14. The clamp screw 228 is prevented from turning by means of a suitable lock screw 230. In order to change the -saw setting from a vertical cut to a 45 bevel cut the operator pulls the lock lever 224 which unlocks the trunnion and the index lever 210 which effects Aa disengagement of the index lug 208 from the notch 206 of the index ange 202. The handle of the levers are in close spaced axial alignment to enable the operator to grasp both simultaneously with .one hand. The motor and trunnion is then turned 45 and the index lever 210 is pushed back again causing the engagement of the index lug 208 with the proper slot 206. The operator then pushes the lock lever 224 back, which, of course, eiects the clamping and locking of the trunnion. This can be done in one motion provided the lever 210 leads. In case it is desired to saw a bevel of 20 or any othervangle where no notch is provided the index lever 210 is left in its forward position indicated by dotted lines in Fig. 16 after the setting is made and only the lock lever 224 is then pushed home to eect the locking of the trunnion. To prevent the index lever 210 from dropping down when in forward position the hub of the latter is provided with a suitable stop lug 232 which engages with the projecting head of the clamp screw 228 when arrivingV at this position.

For the purpose of providing proper heel adjustment for the motor trunnion bearing in the rear fork of the yoke 128, the bearing 234 of the rear motor trunnion 236 is suspended between three easily accessible adjusting screws 238, 239 and 240 (Fig. 17). This arrangement provides a combined micrometer adjustment and and lowered by meansrof a vertical threaded spindle 242 (Figs. l and k137) `which engages with. a conventional ball 1V1ut244.V Y l 'n ,Ball nut 244 is secured to a disc 246 which in'turn l Y by means of screws 248 (Fig. 13)V is mounted in a recess atthe bottom end of the vertical standardror columnV 54.

Y The lower eind of spindle 242is rotatably `supported by a suitable bearing in bracket 250 secured to the lower side of a frame structure 252. The vertical'standard 54 is slidably supported lby a suitable standor base 254 mounted on the topV side of the frame 252. To the standard 54 is secured a key 256 Whichrrun's the entire length of said standard. Key 256 engages With-a suit' able keyway' 258 in the stand 254 and is employed. for the purpose of preventing the standard 54from turning.

. Tothe bottom end of spindler242VY is secured a bevelrg'ear 260 (Fig. 13) meshing with a bevel gear 262 mounted on a horizontal shaft 264 which is rotatably supported in bearing lugs 266 projecting from the bottomjportion of bracket 1259. To one end of the shaft 264 is secured Y top portion carries the radial arm.22a clockwiseoranti clockwise turningV will result in a. raising or lowering of said'radial arm 22. If desired the manually operated crank 272 may be replaced by a suitable reversiblerenduction gearV motorY (not shown).

' Due to theemployment of the/practically frictionless ball nut 244 in conjunction with the weight of the standard.52 and radial arm 22 acting upon the same, the

spindle 242 mayV have a tendency to turn by itself and effect and permit a downward travel ofthe radial arm 22. ToV guard Yagainst such undesired movement the elevating system is provided with av braking device as illustrated in Fig. 13 of the drawings. The brake devicel Y consists of a drum 274 Vsecured Vto the shaft 270 of .the

elevating crank. It could likewise besecured to the shaft Vof a reversible gear reduction motor if desired. However, a gear reduction motor itself serves as a brake and hence Yno further braking means is usuallyy necessary.

Y Drum 274 is in engagement with a Vsteel band 276 which tends to Ybind and lock itselfAto Vthe .drum upon downward rotation. Band 276 on roneend `is suitably secured to -afbracket 278 while the other end is anchoredV to around bar 230 secured to ,the end` of arrscrew 282 which protrudes through a suitable hole in Van upright' rib 2840i bracket 273.v Screw 282 isadjustably heldY by an arm 286 .of a suitable bell ycrank leverj238`pivotally secured to bracket 278 by means of la stud 290. A tension spring 292 surrounding said screw 282 and Yconirined be- 'tween a:nut 294 carried by saidcscrew and the upright rib 284. is provided vto impart tension to thevsteel band 276 Vcontacting Ythe brake drum- 274. This tension Vmay Y V,beadjusted to anyV desired degree. The bandy is released "from the drumby ,simply pressing thebell `crank lever 28S .in the direction of the arrow indicated in Fig. 713./V The elevating system illustrated in Figs `l and 13 is designe/d in such 'a manner that costly spotting and'align- Aingwork during assembly operation'iseliminated. The elevator bracket and its connecting parts, including the standard 54 are assembled separately and then in serted -from theV bottomof the frame Awork Ainto .the already mounted stand 254. The holes '296 .for the mounting screws 293 inithe upper ilange of Vbracket 254) are madeflarge' enough "to Apermit slight Vshifting of the unit if :such shiftingisinecess'ary. The'structure is there- .forenself-.ahgning and -high Vtolerance lexpensive'machin- 'Y ery. is .obviated. The table `safety.extension :is .illustrated 1 .and .2. .This extension :consists of :a -drop leaf 300 which adjacentto its two `side edgesV is securedcto a pair fof suitable bracket members 302 which on one end are pivotally attached to the tableframe V304 of the table T by meansvof suitable bolts 306. To each of the two bracket members 302 ispivotally secured one end of a supporting bar .308 while the free end ofthe latter prof trudes through a slot 310 (Fig. 2) in aebrack'et 312 mountcd'onrthe side of the lfratrie of the machine. A suitable clamp screw V314 supported ina threaded bore of bracket .312 Yis provided for'alockingthe bar Vses in menor 31.0 of

the bracket 312 when the drop leaf 300 is Yin eitherVV raised 'or lowered position. For added safetys sake and to preventthe leaf'300 fromV dropping during operation in case The modified miter indexing and locking mechanism illustrated in Figs. 1.8 and 19 vconsist of a pair ofi clamp shoes 320 and 322 both ofY which are positioned to en gage Ywithfthe top end 572 of the-vertical column or standard 54. Each shoe ,320 and 322 is provided with a pair of lugs 324 andr326, and 32S and 330, respectively, by means of which `said shoes are supportedby a clamp shoe bolt 332. The latter is rotatably supported in suitable .bearings in the radial arm 334 which is substantially of the same design and construction as the radial arm 22 shown in Figs. l, 2,13v and 4'with the exception that arm .334 in Figs. 18 and 19 is provided Vwith only a partial or semicircular hub 336 with which itY engages with .the ,upper portion 52 of column 54. The Clamp bolt 332 Vadjacent. each end is provided with two steppedrbearing 320 loosely engages -with the smooth 'bearing portion V338 of bolt 332 while lug 326 of the same shoe engages freely with the smooth stepped down center portion 342. Loosely in the space between'lugs 324 and 326 ofclarnp shoe 320 -but tightly secured to the portion 342 ofbolt .332 is located a shoe wrench -lever 346. The latter on Vits free endris pivotally connected to the rod 38 of identical .construction and same function as the one show n in Figs. .1, .2, 3, and 4,'so that when the actuating lever 20 is lifted by the operator the vclamp Vbolt 332 is caused Vto 'turn and thus effecting anunclamping of the shoes 320 Vand322 from. .the upper portion 52 of the column and consequently an unclamping ofthe radial arm -from Vsaid column. VAdownward.movement of lever 20, of course, vclamps 'the shoes against the columnand locks the radial arm' again.

The radial Varm 334 shown inrFigs. 18 andk 19Vis also Yequipped with a modified miter indexing deviceLwhich consists of a conical-plunger 348 ,designed to engage with `one of the three holes 350 spaced 45 apart in .the indexing disc 352 which is of similar design and construction as 'the disc` 72 illustrated in Figsp3, 4, and Y5,"with the vexception that conical holes instead of Vslots are provided. The indexing disc 352, of course, is also secured Vto the upper portion. 52V of the *vertical column 54 by means of clamp screw V353 (Fig. V19) andthe lower --fac'e Vof the hub of the radial arm 334 rests rotatably on vrthe face of the index disc 352 inthe same manner as in connection to the same cable arrangement as illustrated in Figs. 1, 2, 3 and 4, of the preferred embodiment. An upward pull on the activating lever 20 will effect the raising of the plunger 348 in the same manner as described heretofore.

The accurate setting and adjusting of the miter index disc 72 yfor the radial arm 22 illustrated in Figs. 3, 4 and 5 is accomplished by the proper setting of the two opposed set screws 360 which contact the side edges of the rigidly mounted key 256 on column 54 which projects into an opening in said disc. By loosening clamp screw 74 of index disc 72 and adjusting the set screws 360 the most accurate setting of the index may be attained. v

In the modified construction shown in Fig. 19, the key 256 does not project into the index disc 352 but a short separate key 362 is provided. The latter is secured to the rear of the column 54 by means of screws 364 and projects into a wide slot in said index disc 352. A pair key in the same manner as the screws illustrated in Fig. of opposed set screws 366 contact the side edges of said 5 of the preferred embodiment.

I claim:

1. In a radial arm power tool, a base, a work support table on said base and an arm extending across and spaced vertically from said work supporting table, a carriage longitudinally movable along said arm, said carriage having a bottom plate-like member, a tool supporting yoke having an upper portion formed with a plate-like member, said plate-like members having registering bores formed therein, a kingpin in said bores, said kingpin having means to support said yoke, said kingpin extending upwardly above said upper plate-like member, an annular helical guide on said upper extending portion of said kingpin, a lever having one end free and having its other end about said upwardly extending portion of said kingpin and having helical means to engage said annular helical means to move said lever axially of said kingpin as the free end of said lever is moved about said kingpin to thereby draw said kingpin upwardly in one direction of movement of said lever to draw said plate-like members together and in frictional engagement to prevent movement of said yoke member about said carriage member, said yoke having at least one formed engageable surface thereon at a predetermined angular position about said kingpin, a movable pin mounted on said carriage and movable to engage said formed surface when in rotary register therewith, said pin being biased to move into engagement with said engageable surface, a crank mechanism operative when rotated to move said pin against its bias and out of Contact with said surface, and a structure on and projecting from said lever to engage said instrumentality when said lever is swung in one direction and to disengage said instrumentality when said lever is swung in the opposite direction.

2. In a tool of the type described, the combination of a base, a work supporting table on said base, a vertical column positioned rearwardly on said table, an arm supported above said table and operatively supported on said vertical column for swinging movement across said table in a substantially horizontal plane, an anti-friction carriage operatively supported on said arm for longitudinal movement therealong, frictional locking means operatively carried by said arm and movable between a plurality of positions, said frictional locking means being operative in one position to engage side portions of said vertical column and prevent said arm from Ibeing swung across said table, said frictional locking means being operative iu other positions to permit said arm to be swung, a plate mounted on said column and having a plurality of indexing surfaces, a lug carried by said arm, said lug being movable relative to said arm between a iirst position, in which said lug is in engagement with one of said indexing surfaces, and a second position, in which said lug is disengaged from said indexing surfaces, a first single lever mounted upon said arm and operatively connected to consecutively i@ move said lug and said iirst frictional locking means between said rst and second positions, a yoke beneath said carriage, said yoke and said carriage having axially aligned bores, a kingpin operatively positioned in said bores t0 support said yoke, said kingpin having a portion extending upwardly beyond the bore in said carriage, said portion of said kingpin being threaded, a second lever having a free end, the other end of said lever being provided with a threaded bore operative to engage said threaded portion of said kingpin so that movement of said second ever about said kingpin will secure said yoke member against rotary motion with respect to said carriage and said kingpin will support said yoke member on said carriage, said yoke having at least one indexing surface, a lug mounted on said carriage for movement to engage and disengage said indexing surface on said yoke, a crank mechanism operative when rotated to move said ylug into disengaged position with respect to said indexing surface, and an instrumentality flxedly mounted on said lever to rotate said crank mechanism whereby said lug is moved into an operative position when said lever is moved in one direction.

3. In a woodworking tool, the combination of a base, a work supporting table on said base, a vertical column disposed rearwardly of said base, an arm supported above said table and operatively supported on said vertical column for swinging movement across said table in a substantially horizontal plane, frictional locking means operatively carried by said arm and movable between positions, said frictional locking means operative when in one position to engage side portions of said vertical column and prevent said arm from being swung, said frictional locking means operative in other positions to permit said arm to be swung, a plate mounted upon said column and having indexing surfaces, a lug carried by said arm, said lug being movable relative to said arm between a rst position in engagement with one of said indexing surfaces and a second position disengaged from said indexing surfaces, and a single lever mounted upon said arm and being operatively connected to consecutively move said lug and said frictional locking means between said rst, second, other and one positions.

4. In a woodworking tool, the combination of a base, a work supporting table on said base, a vertical column disposed rearwardly of said base, an arm supported above said table and being operatively supported on said yvertical column for swinging movement across said table in a sub stantially horizontal plane, fn'ctional locking means operatively carried by said arm and movable between a series of positions, said frictional locking means operative when in one position to engage said vertical column and prevent said arm from being swung, said frictional locking means operative in other positions to permit said arm to be swung, a plate mounted upon said column and having indexing surfaces, a lug carried by said arm, said lug being movable relative to said arm between a irst position in engagement with one of said indexing surfaces and a second position disengaged from said indexing surfaces, a rotatable bolt operatively connected -to move said frictional engaging means Ibetween said one and other positions, a. wrench connected to rotate said bolt and movable between said first and second positions, and a single lever mounted upon said arm and being operatively connected to rotate said wrench to Vmove said lug and said frictional locking means between all of said positions in response t0 movement of said lever.

5. In a woodworking tool, the combination of a base, a work supporting table on said base, a vertical column disposed rearwardly of said lbase, an arm supported above said table and lbeing operatively supported on said vertical column for swinging movement across said table in a substantially horizontal plane, frictional locking means operatively carried by said arm and movable between certain positions, said frictional locking means operative when in one position to engage said vertical coltn nnj and prevent said arm from being swung, said frictionalelocking means operative in other positions to per- Y mit arm tobe swung, a plate mounted upon said column and having 'indexing-surfaces, a lug carried by Y said arnnsaid lug being movable'relative` to said arm between a first position in engagement with onev of saidl indexing surfaces and a ,second positionivdisengaged from said' indexing surfaces, lost` motion means connected to said lug, and a single lever mounted upon said arm and Y beingV operatively Vconnected to said lost motion means and to said frictionai locking means whereby said lug and said frictional'locking means are consecutively operated.

. 6. In a woodworking tool, the combination of a base, a work support-mg tableon said'base, a vertical column disposed rearwardly of said base, Van arm operatively connected adjacent Yto one end' thereof to said vertical column Vrotatable in a horizontal plane across said i table,ithe other end of said armv extending outwardly across Vsaid table; va plateemounted upon said vertical column adjacent to said armY and having engageable surfaces at predetermined positions, a lugioperably carried by said arm for movement therewith, said lug beingfur- Y thermovable'relative .to said arm and engageable with said engageable surfaces to index said arm, frictional engaging means operable to engage side portions of said vertical column 4andiprevent rotation of said arm when s aid frictional engaging means is inl one position, and a single vlever means mounted adjacent to .the other end of said arm and operably conneotedto said lug and said frictional engaging means Vto consecutively move .the same into engaging position in response to movement of lsaid lever means.

Y 7,. in a power tool, the combination of a base, a work supporting table on said base, an arm positioned above said work supporting table, a tool supporting carriage adapted to reciprocate along said arm, said carriage having a vertical central bore, a yoke 'beneath said carriage,4 said yoke having a .bore in axial alignment with said carriage bore, .a kingpin operatively positioned in said bores to support said yoke, a portion of said kingpin extending upwardly beyond the bore in said carriage,

"said portion of Vsaid kingpin being threaded, ya lever haverative when contacted Yto move-said lug into a disengaged position with respect to said indexing surface, anV in-Y strumentaiity projecting outwardly from4 said leverto contact said mechanism, said arm carrying a longitudinal stationary brake elem-ent, said kingpinhaving a Vsubmova'ole between engage-d and disengaged Vpositions with respect to said-brake element, and a movable pin in sa'idboreV operatively connected to move'said clamping means, said pin being movable to operatively engage said brake element on said yarm when said clamping means is in said engaged'position to frictionally arrest the movement of said carriage at any position along said arm.

S.. In apower tool, the combination of a base, a Work supporti@l table on said base, an armpositioned above said Vwork supporting table, a tool supporting carriage adapted to reciprocate along-said arm, said carriage hav, ing aV vertical central bore, a yoke supported beneath Ysaid carriage, said yoke having a bore in axial alignment with said bore `of said carriage, a kingpin operatively positioned in said boresY to support Vsaid yoke, a portion of said kingpin extending upwardly beyond the. borel in said carriage, said portion being threaded, a lever having aifreeendjthe other end of'said lever being provided stantiaily axial vertical bore therethrough, clamping means Y with a threaded. boreV operativeto engage said threaded portion of said kingpin so that movement of, said; lever about said' kingpin'wiil'securesaid yoke member against rotary motion Awith respect .to said carriage and Ysaid kingpin will support said yoke member `on 'said-carriage, said yoke having at least one indexing surface, a'lug mounted on said .carriage for movement toengage and disengageesaid indexing surface, a mechanism operative when contacted to move said lug into a disengaged position-With respect to said indexingsurface, an instrumental-` ity rigidly mounted on said lever to contact said mechanism, said arm carrying'a longitudinalV stationary'brake element,said kingpin having a substantially axial vertical Vbore therethrough, a C-shaped clamp disposed above said vertical bore of said kingpin and movable betweenY a rst position in engagementV with said brake element and a second position'disengaged from 'saidbrake element, saidclarnp being provided )with a threaded portion, and a movable pin disposed in said. bore and being provided at its upper end with a threaded portion inrengagement with .the threaded portion ofsaid clamp, said pin being movable to operatively engage said brake element when said clamp is in said engaged position-,to frictionally arrest theV movement lof said carriage at any position along said arm.

9. In a power tool, the vcombination of a base, a work supporting table on said base, an arm positioned above said work supporting table, a tool supporting carriage adapted to reciprocategalong said arm, said carriage havinga vertical central bore formed therein, a yoke beneath said carriage, said yoke having a .bore Yformed therein inl axial alignment with said carriage bore, a kingpin operatively positioned in said bores to support said yoke, said kingpinextending upwardly beyond the bore in said carriage, said extended portion of saidkingpin having. threads. formed thereon, a lever having a free end and having formed at its other end a threaded bore operative Ito, engage said threaded portions Vof said kingpin, so that movement of said lever labout said kingpin will secure said yoke member from rotary motion with respect to said .carriage and said kingpin will support said yoke member to said carriage, said yoke having Vat least one engageable surface formed thereon, `a movable lug movably mounted on said carriage `and movableV to engage and disengage said engageablesurrace, al crank mechanism operative when rotated to move said lug Vinto nonsurface engaging position, Vand an instrumentality fixedly mounted on said vlever to rotate .said mechanism whereby saidv lug is moved Vinto inoperative position when said lever is moved in one direction. i,

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